How & When to Prune Trailing Vinca Vines

Vinca

• Vinca is also called periwinkle or trailing myrtle and is available as two slightly different plants. Lesser periwinkle (Vinca minor) is about 3 to 6 inches tall, spreads to cover about 1 1/2 feet, has shiny green leaves and produces lavender flowers in May and June. It grows in U.S. Department of Agriculture plant hardiness zones 4 through 8. Greater periwinkle (Vinca major) is a bit taller, about 6 to 18 inches, and spreads to cover about 2 feet. It's less hardy than the smaller plant, growing in USDA zones 7 through 9, and has blue-to-purple flowers in April and May.

Timing

• Both types of periwinkle produce trailing, arching stems that spread across the ground and can root wherever they touch soil. Grown as a ground cover, periwinkle can spread rapidly, sometimes expanding out of bounds and crowding out other plants. When container-grown, the plant sends its stems cascading over the rim of its pot. They can become quite long, possibly touching the ground and spontaneously rooting. Although you can prune the plant at any time, cutting it back in early spring won't interfere with its flower production, because the plant blooms on new wood. Spring pruning also allows a full season for new growth to fill in a garden area.

Method

• Pruning periwinkle is best done with garden pruners or shears, heading back vines by cutting straight through stems just ahead of a pair of leaves. If a planting is thick with overgrowth, you could cut back all stems to within 3 or 4 inches of each plant's base, allowing new growth to renew the plant. If your periwinkle planting is large, mowing over the entire patch can help control its sprawl and stimulate the plants to put out vigorous new stems.

Other Issues

• Because both greater and lesser periwinkle can spread quickly and re-sprout from stem fragments, both plants have invasive potential in some parts of the U.S. When pruning back a patch of cultivated periwinkle, remove and discard stem cuttings. Using a barrier system around a planted bed can help inhibit spread of roots. Periwinkle is not a good choice for an area near the edge of a woods or naturalized planting, because it might invade this area and choke out native plants. If you have pets or children, periwinkle may not be a good option for you, because all parts of both varieties contain toxic chemicals and are poisonous if ingested.